Thermometer



May 19, 1925.

E. N. HURLBURT THERMOMETER File@ June 20, 1923 INVENToR.

Patented May 19, 1925. l

:UNITED STATE S APiflrislarfor-F1ce.;

EDWARD N. HURLEURT, or ROCHESTER, NEW YoRx, AssIeNoR To TAYLOR INsTRU- MENT cos., or ROCHESTER, NEW YORK, A CORPORATION E NEW YORK.

.TEERMOMETER Application mea :une 2o, 192s. serial No. 646,506.

To all whom it may concern.'

Be it known'that I, EDWARD N. HURLBURT,

a citizen of the United States, residing` at Rochester, in the county ofv Monroe and 5 State of New York, have invented' certain vnew and' useful Improvements in Thermome# ters; and I do hereby declare the following to Ybe a full, clear, and exact descriptionof the same, reference being had to the accompanying drawings, forming a part of this specification, and to the reference numerals marked thereon.

This invention relates to thermometers of the variety comprising a tubular stem and bulb containing an expansible fluid with markings on the stem for reading temperatures indicated by the expansion of the Huid, one object of the invention being to provide an accurate and durable thermometer of this' type particularly adapted in form and art rangement for being thrust into a substance such, for example,as meatfor exploring-the interior temperatures thereof during sterilizingtreatrnent. A further object is to provide such an instrument having an improved form of armor or sheathing sov constructed and applied as to a'ord a maximum of conductivity between the substance to be tested and the thermometric iuid for purposes of 30 accuracy, as Well as features of size and shape adapting it for penetrating with ease the material to be tested.

To these and other ends 'the invention resides in cert-ain improvements and combina- 3 fully described, the novel features being pointed outin the claims at the end of the specification.

In'the drawings: Fig. l is an elevation of a thermometer embodying the present invention; Fig. 2 is a similar view with a casing portion removed;

Fig. 3 `'s an enlarged longitudinal sectional view partly broken away and;

Fig. 4 is an enlarged section on' the line` such tions of parts all as Will be hereinafter more having alminimum diameter.' consistent with the requlrements of strength in the completed instrument and terminating in an elfec-v tively -pointed bulb adapted to-be readily thrust-to a substantial distance into the material tobe tested. -The bulb is a least as small 'in diameter as the elon ated stem and quite sharply pointed to facllitate penetration into the material, the bulb and the stem. portions being encased in a sheath of metal as copper electrolytically depositedl thereon. The other or scale portion of the tube is provided with a metal sleeve or casing overlapping and firmly. united with the copper plating, with a sight opening or window through which the scale is lvisible, sov

that the Whole instrument is fully reinforced .and protected by metal armor applied yin such a manner'at the bulb portion as to afford maximum conductivity andaccuracy.

Referring more' particularly to the drawings, there is shown at' 5, the scale portion ofthe-l tubula'r glass member formlng the thermometer proper. This portion preferablyhas a substantial diameter 'forreceiving a scale 6 of sufficient proportions to enable v it to be quickly and easily read. Atthe loWer end of this scale portion, the diameter of the tube is reduced to form a relatively slim, lancelike stem portion 7, having a length adapting it for penetrating toa considerable distance into the material to be tested. This stem portion terminates in a bulb 8 of the-same diameter asy the stem and having a sharply pointed end 9. At 10 is the sensitive Huid, 1n the y present instance,

mercury. 1

' The stem and bulb stated are given a minimum diameter oon'- sistent with the necessary vstrength in the fnished instrument and are reinforced by a sheathing or armor or copper plating 11. It

a is desirable for purposes of accuracy that such sheathing be at all points inintimate contact with the glasssurface and' united therewith in order that the heat may be quickly and complete-ly transmitted to the glass and the sensitive fluid, and such con-l portions as already I struction obviously increases,l the strength and compactnes'sa's Well. To4 this end the stem and bulb portionsare first coated as at 12 with an electrically conductive film, such as silver, deposited thereon by chemical action, as well understood vin the art. This coating is, of course, fixed on andin intimate association with the glass surface and serves as a conductor for electrolytically depositing on the bulb and stema sheath of metal plate.

- The metal preferred for this purpose is copp'er'and it is deposited in aplate of sufficient posed in use -While at the 'same time, due to its method of formationfbeing united with i the'slver film-and the glass.- The long -exploring stem is thus rendered, practically unbreakable b a sheath or armor Which presents no inter erence to the rapid conduction of vheat to the sensitive Huid;

The copper sheath of the stem portion is extended beyond the shoulder l'formed at the junction of the stem and scale portions and `for a substantial distance on the latter.l

A casing 14 is provided for the scale portion of the tube in the nature of a metal sleeve y positioned to overlap the copper plating l5 on the lower end ofthescale portion and closely fitting the same with the end of theV casing rolled inwardly asp-at -16 around the ing is externally threaded as at 19 and receives a cap 20, provided with a lug 21 having a bearing 22 for aconvenient suspension ring 23. `A plug of felt, cork or other suitl able material 24l`is preferably interposed beltween the end of the thermometer tube .and

the top of the cap so that as the latter is screwed homeon the casing, the thermometer is by this means further securedin the C position described.

The invention thus provides an efficient instrument having a high degree of accuracy and conveniently adaptedV 1n form and arrangement for-the purposes specified. The construction furthermore affords a strong and durable thermometer which may` be manufactured at a comparatively lovi7 cost.

I-claim as my invention.:

1. A thermometer comprising4 a lglass tube having a scaleportion and an elongated stem portion terminating 'in a bulb of substantially the same diameter as thestem and provided With a pointed end for piercing material to be tested, a reinforcing metalsheath electrolytically deposited on the surface -of said bulb and stemportion and a protective metal casing for said scale portion extending at one end into overlapping relation with l'said sheath Y and having a sight Y opening through which the scale is visible.

2. A thermometer comprising a glass tube having a scale portion and an elongated stem portion terminatingA in ,a .bulb of substantially' the same diameter as the stem and provided with apointed end for piercing matcrial to be tested, said stem portion having a diameterless than that of said scale portion forming a shoulder at the junction of said portions, a reinforcing metal sheath electro- Hlytically deposited on the surface of said bulb and stem portion and the contiguous end of said scale portion, a protective metal casingffor said scale portion having an end thereof overlapping said sheath and rolled over said shoulder to afford rigid engage mentwith the'sheath and provided with a sight opening through which the scale is visible, and a cap engaged With the other end of said casing and 4.with said tube for vsecuring the casing thereon.` l i A EDWARD N, HURLB-un'r. 

